Characterization of the development of the high-acuity area of the chick retina.

The fovea is a small region within the central retina that is responsible for our high acuity daylight vision. Chickens also have a high acuity area (HAA), and are one of the few species that enables studies of the mechanisms of HAA development, due to accessible embryonic tissue and methods to readily perturb gene expression. To enable such studies, we characterized the development of the chick HAA using single molecule fluorescent in situ hybridization (smFISH), along with more classical methods. We found that Fgf8 provides a molecular marker for the HAA throughout development and into adult stages, allowing studies of the cellular composition of this area over time. The radial dimension of the ganglion cell layer (GCL) was seen to be the greatest at the HAA throughout development, beginning during the period of neurogenesis, suggesting that genesis, rather than cell death, creates a higher level of retinal ganglion cells (RGCs) in this area. In contrast, the HAA acquired its characteristic high density of cone photoreceptors post-hatching, which is well after the period of neurogenesis. We also confirmed that rod photoreceptors are not present in the HAA. Analyses of cell death in the developing photoreceptor layer, where rods would reside, did not show apoptotic cells, suggesting that lack of genesis, rather than death, created the "rod-free zone" (RFZ). Quantification of each cone photoreceptor subtype showed an ordered mosaic of most cone subtypes. The changes in cellular densities and cell subtypes between the developing and mature HAA provide some answers to the overarching strategy used by the retina to create this area and provide a framework for future studies of the mechanisms underlying its formation.

Modulations of foveal vision associated with microsaccade preparation.

It is known that attention shifts prior to a saccade to start processing the saccade target before it lands in the foveola, the high-resolution region of the retina. Yet, once the target is foveated, microsaccades, tiny saccades maintaining the fixated object within the fovea, continue to occur. What is the link between these eye movements and attention? There is growing evidence that these eye movements are associated with covert shifts of attention in the visual periphery, when the attended stimuli are presented far from the center of gaze. Yet, microsaccades are primarily used to explore complex foveal stimuli and to optimize fine spatial vision in the foveola, suggesting that the influences of microsaccades on attention may predominantly impact vision at this scale. To address this question we tracked gaze position with high precision and briefly presented high-acuity stimuli at predefined foveal locations right before microsaccade execution. Our results show that visual discrimination changes prior to microsaccade onset. An enhancement occurs at the microsaccade target location. This modulation is highly selective and it is coupled with a drastic impairment at the opposite foveal location, just a few arcminutes away. This effect is strongest when stimuli are presented closer to the eye movement onset time. These findings reveal that the link between attention and microsaccades is deeper than previously thought, exerting its strongest effects within the foveola. As a result, during fixation, foveal vision is constantly being reshaped both in space and in time with the occurrence of microsaccades.

Associations of community-level particulate matter with high-acuity visit presentation for sinusitis.

BACKGROUND: Exposure to particulate matter <2.5 µm in diameter (PM2.5) has been linked to increased sinusitis prevalence and morbidity. However, studies analyzing environmental exposures and sinusitis have not explored the effect of PM2.5 on healthcare presentation patterns. OBJECTIVE: This study aims to characterize the relationship of community-level PM2.5 with high-acuity visits in sinusitis patients. METHODS: A retrospective analysis based on medical records of 2092 adults presenting with chronic rhinosinusitis, acute rhinosinusitis, or sinus/nasal polyps to an urban academic medical center from 2010 to 2019 was conducted. We linked medical records (individual-level) with data on PM2.5 exposure at the community level, using residential zip-code data from the Chicago Health Atlas covering the years 2015-2019. Multivariable binary logistic regression with Generalized Estimating Equations examined adjusted associations between PM2.5 and high-acuity visits - including emergency department and inpatient settings. RESULTS: Our sample was 69 % female, with a mean age of 46.9 years. From 2015 to 2019, the average PM2.5 exposure in zip-codes examined was 11.66 µg/m3 with a range of 11.14-11.79 µg/m3. In adjusted models, odds of a high-acuity visit were significantly higher in patients residing in zip-codes in the top tertile of PM2.5 exposure compared to the bottom tertile (OR: 1.74; CI: 1.20-2.51). CONCLUSION: Community-level PM2.5 exposure was associated with high-acuity visits among sinusitis patients. These associations need to be studied through more rigorous, prospective investigations, as they may have potential public health implications and underscore a need to mitigate PM2.5 exposures at a community-level.

An Epidemic Within the Pandemic: The Rising Tide of Trauma During COVID-19.

BACKGROUND: In the age of COVID-19 and enforced social distancing, changes in patterns of trauma were observed but poorly understood. Our aim was to characterize traumatic injury mechanisms and acuities in 2020 and compare them with previous years at our level I trauma center. MATERIAL AND METHODS: Patients with trauma triaged in 2016 through 2020 from January to May were reviewed. Patient demographics, level of activation (1 versus 2), injury severity score, and mechanism of injury were collected. Data from 2016 through 2019 were combined, averaged by month, and compared with data from 2020 using chi-squared analysis. RESULTS: During the months of interest, 992 patients with trauma were triaged in 2020 and 4311 in 2016-2019. The numbers of penetrating and level I trauma activations in January-March of 2020 were similar to average numbers for the same months during 2016 through 2019. In April 2020, there was a significant increase in the incidence of penetrating trauma compared with the prior 4-year average (27% versus 16%, P < 0.002). Level I trauma activations in April 2020 also increased, rising from 17% in 2016 through 2019 to 32% in 2020 (P < 0.003). These findings persisted through May 2020 with similarly significant increases in penetrating and high-level trauma. CONCLUSIONS: In the months after the initial spread of COVID-19, there was a perceptible shift in patterns of trauma. The significant increase in penetrating and high-acuity trauma may implicate a change in population dynamics, demanding a need for thoughtful resource allocation at trauma centers nationwide in the context of a global pandemic.

Perioperative Skeletal Muscle Fluctuations in High-Acuity Liver Transplantation.

BACKGROUND: Frailty has been implicated as a negative predictor of Liver Transplant (LT) outcomes. However, an understanding of changes in patient muscle mass peri-LT, and their effect in high-acuity patients remains lacking. We examined the impact of perioperative muscle mass changes (ΔSMI) on high-acuity (MELD ≥35) LT recipients. MATERIALS AND METHODS: Skeletal muscle index (SMI) was calculated using CT imaging. Patients were divided into two groups, based on severity of peri-operative SMI decrease. LT recipients with chronic end-stage liver disease, MELD ≥35, and abdominal CT ≤30 days prior, and 30-90 days post LT were included. [1011 adult LT recipients reviewed, 2012-2018]. RESULTS: Of 1011 patients reviewed, 88 met inclusion criteria (median MELD 41.1). The median ΔSMI was -5.0 (-29.4 - +21.1 cm2/m2) (fig A). Patients were classified into two groups: ΔSMI<-5.0 (median ΔSMI: -0.4, n = 44) and ΔSMI>-5.0 (median ΔSMI: -9.2, n = 44). Recipients with ΔSMI<-5.0 had higher pre-LT SMI (35.4 versus 31.2 cm2/m2, P <0.001) and lower post-LT SMI (26.0 versus 30.8 cm2/m2, P <0.001). The ΔSMI<-5.0 group had higher early allograft dysfunction (40.9 versus 20.5%, P = 0.037), and inferior patient and graft survival (P = 0.015, 0.017, respectively). Multivariate analysis identified ΔSMI<-5.0 (HR: 2.938, P = 0.048), long cold-ischemia time (≥9h, HR: 7.332, P = 0.008), HCV (HR: 5.614, p = 0.001), and tracheostomy after LT (HR:9.218, P <0.001) as negative prognostic factors for patient survival . CONCLUSIONS: Progressive perioperative sarcopenic deterioration was associated with inferior patient and graft survival in high acuity LT. These findings may guide pre and post-operative patient care and rehabilitation efforts in this challenging patient population.

The Impact of Previous Abdominal Surgery in a High-Acuity Liver Transplant Population.

BACKGROUND: It is not uncommon for liver transplant (LT) recipients to have had previous abdominal surgery (PAS) preceding transplant. The impact of PAS on morbidity and mortality in LT patients remains unclear. In this study, we investigated the correlation between PAS and LT outcomes in a high-acuity patient population. MATERIALS AND METHODS: This is a single-center retrospective review of 936 adult primary LT recipients between 2012 and 2018. Patients were divided based on PAS history. PAS was subdivided into upper abdominal surgery (UAS) and lower abdominal surgery (LAS). UAS was separated into high-impact UAS and low-impact UAS. Finally, we studied patients with PAS ≤90 d versus PAS >90 d. RESULTS: Extensive adhesiolysis was the only significant perioperative factor between the PAS group (n = 367) and the non-PAS group (n = 569) (P < 0.001). Red blood cell (RBC) transfusion (20U versus 17U, P = 0.044) and abdominal packing (24.2% versus 13.3%, P = 0.008) were significantly higher in the UAS group (n = 186) versus the LAS group (n = 181). Patients with high-impact UAS required greater RBC (P = 0.021) and fresh frozen plasma transfusion (P = 0.005), and arterial conduits (P = 0.016) during LT. Compared with recipients with PAS >90 d (n = 338), recipients with PAS ≤90 d (n = 29) had significantly higher RBC transfusion (P = 0.046), fresh frozen plasma transfusion (P = 0.022), and abdominal packing (P = 0.025). No differences in patient and graft survival was observed. CONCLUSIONS: These findings suggest that, with appropriate care in the perioperative setting, PAS is not a contraindication to successful LT. Careful consideration is warranted when risk stratifying patients with multiple comorbidities who had PAS, especially those with UAS or PAS ≤90 d.

Retrospective Chart Review: Readmission Prediction Ability of the High Acuity Readmission Risk Pediatric Screen (HARRPS) Tool.

BACKGROUND: Nurse Case Managers utilize adult based readmission risk tools upon admission to identify readmission risk. An evidence-based pediatric readmission tool could not be identified to replicate in the pediatric space, therefore the High Acuity Readmission Risk Pediatric Screen (HARRPS) Tool was developed to fill this gap. The research aim was to develop a risk score algorithm that accurately predicts pediatric readmissions and provide a predictive validation of the HARRPS Tool. METHOD: This was a single-centered, retrospective chart review study which compared pediatric patients with thirty-day readmissions to those without thirty-day readmissions over a twelve-month period. Sample size ratio of 1:2 was determined via power analysis with an overall sample size of 5371. Each category from the HARRPS Tool was appropriately weighted based upon data from this study to then produce an overall, patient-level risk score, which was summed [allowable range: 0, 14] across all components. Cross validation was used to ascertain the readmission risk predictability. RESULTS: Of the 5306 patients included in the final analysis, 1343 (25.3%) had a thirty-day readmission. Out of nine risk components analyzed, eight were consistent with the literature review findings. Patients with a score of seven or higher had a 54.9% predicted probability of a thirty-day readmission, compared to 13.6% for patients with a risk score of zero. The c-statistic score of the HARRPS Tool was determined to be 0.68 [95% CI, 0.67, 0.69]. Overall, the HARRPS Tool was favorable and provides initial credibility of the tool's predictive power for the general pediatric population.

Palliative homecare is associated with reduced high- and low-acuity emergency department visits at the end of life: A population-based cohort study of cancer decedents.

BACKGROUND: Prior work shows that palliative homecare services reduce the subsequent need for hospitalizations and emergency services; however, no study has investigated whether this association is present for emergency department visits of high acuity or whether it only applies to low-acuity emergency department visits. AIM: To examine the association between palliative versus standard homecare nursing and the rate of high-acuity and low-acuity emergency department visits among cancer decedents during their last 6 months of life. DESIGN: This is a retrospective cohort study of end-of-life homecare patients in Ontario, Canada, who had confirmed cancer cause of death from 2004 to 2009. A multivariable Poisson regression analysis was implemented to examine the association between the receipt of palliative homecare nursing (vs standard homecare nursing) and the rate of high- and low-acuity emergency department visits, separately. RESULTS: There were 54,743 decedents who received homecare nursing in the last 6 months of life. The receipt of palliative homecare nursing decreased the rate of low-acuity emergency department visits (relative rate = 0.53, 95% confidence interval = 0.50-0.56) and was significantly associated with a larger decrease in the rate of high-acuity emergency department visits (relative rate = 0.37, 95% confidence interval = 0.35-0.38). CONCLUSION: Receiving homecare nursing with palliative intent may decrease the need for dying cancer patients to visit the emergency department, for both high and low-acuity visits, compared to receiving general homecare nursing. Policy implications include building support for additional training in palliative care to generalist homecare nurses and increasing access to palliative homecare nursing.

Belonging in high acuity settings: What is needed for newly graduated registered nurses to successfully transition? A qualitative systematic review.

BACKGROUND: A worldwide shortage of nurses providing clinical care, coupled with an increase in severity of illness of hospitalised patients has led to newly graduated Registered Nurses being placed into high acuity settings, such as the emergency department, intensive care unit and operating theatre. The feeling of belonging in these settings impacts on successful transition of newly graduated Registered Nurses, their learning, and may lead to high attrition rates. OBJECTIVE: To comprehensively synthesise qualitative research on newly graduated Registered Nurses' experiences of belonging, while working in high acuity clinical settings. DESIGN: Elements of the Joanna Briggs Institute (JBI) systematic review protocol were utilised. The Preferred Reporting Items of Systematic reviews and Meta-Analyses (PRISMA) guidelines were used to conduct the review. Data were analysed using thematic analysis. DATA SOURCES: Ovid Emcare, PsychInfo, CINHAL, Proquest and Scopus. METHODS: The PICo (population, interest and context) strategy was used as a guide to develop search terms. Published literature from January 2007 to April 2021 was searched. Screening, selection and data extraction were performed by two authors independently. All discrepancies were resolved through discussion with a third reviewer. RESULTS: A total of 506 studies were identified following the systematic search; after duplicates were removed, 440 were screened by title and abstract and 29 by full text. Six articles were included in this systematic review. Methodological quality was assessed utilising the JBI critical appraisal checklist, and discrepancies ratified through team consensus. The themes; emotional lability, structured program design, preceptors' influence and acceptance were identified. CONCLUSIONS: Newly graduated Registered Nurses in the high acuity setting feel emotionally insecure related mainly to their educational unpreparedness. They have need for a structured program, inclusive of both theory and supported practice. The role of the preceptorship team is vital in enabling a feeling of belonging, as is acceptance by nursing staff of the learning journey.

Establishing consensus-based high-acuity low-occurrence skills for EMS physicians: A pilot survey of EMS fellowship faculty.

Background: The specialty of emergency medical services (EMS) medicine focuses on providing out-of-hospital patient care, including initial stabilization, treatment, and transport in specially equipped vehicles including ambulances and airframe platforms to hospitals and better-resourced destinations. The Core Content of EMS Medicine outlines the knowledge, procedures, and psychomotor skills relevant to prehospital patient care. However, this document does not specify the high-consequence skills that are infrequently performed and that carry high levels of complexity as well as potential morbidity. We refer to these as high-acuity low-occurrence (HALO) skills. Additionally, there is no consensus definition of what meets the criteria for a HALO skill. The goals of this pilot study were twofold: (1) to determine a consensus definition for a HALO skill and (2) to survey EMS fellowship faculty to identify an initial set of EMS physician trainee skills that meet the HALO definition. Methods: Using a modified Delphi method, we established a consensus definition of a HALO skill as well as skills that met this definition for EMS physicians. Demographic information was collected from the experts. Results: There was 100% agreement in the definition provided of a HALO skill. No additional proposed definitions were provided. Thirteen HALO skills were suggested by the panel from the originally proposed 56 skills, requiring three rounds to establish consensus. Final skill domains emphasized by the expert panel include airway management, obstetric emergencies, and shock management. Conclusions: We present an initial consensus definition of a HALO skill and a recommended list of HALO skills for EMS physicians in training. Opportunity exists for further research to validate the definition and list of HALO skills through the sampling of a broader group of EMS physicians.

Demographic Factors and Comorbid Conditions Related to Health Care Presentation Among Patients With Sinusitis.

BACKGROUND: Social determinants of health (SDOH) and comorbid conditions (CMCs) influence the setting of presentation for care; however, few studies have explored this relationship in the context of sinus disease. OBJECTIVE: This study aims to characterize the relationship of SDOH and CMCs with acuity of health care presentation setting in adults with sinusitis. METHODS: A retrospective analysis based on medical records (demographics, visit types, and ICD-10 codes) of 1842 adult patients presenting with sinusitis to an urban academic medical center was conducted. Chi-square analysis was used to assess bivariate associations of SDOH (age, race/ethnicity, sex, insurance type, and employment status) and CMCs (depression, body mass index [BMI], allergy, and gastroesophageal reflux disease [GERD]) with high-acuity visit types-including emergency department (ED) and inpatient visits. Multivariable binary logistic regression was performed to examine the adjusted associations between SDOH and high-acuity visits. RESULTS: The sample's mean age was 46.8 years, with 68.5% females and 31.5% males. In adjusted models, the odds of high-acuity visit presentation was higher for males than females (odds ratio [OR]: 1.57; confidence interval [CI]: 1.22-2.01); non-Hispanic Blacks (OR: 2.21; CI: 1.58-3.09) as well as Hispanics/Latinos (OR: 2.10; CI:1.43-3.08) than Whites; unemployed (OR: 1.90; CI: 1.47-2.46.) than employed. Age was positively associated with high-acuity presentation. While GERD was associated with increased odds of high-acuity presentation (OR: 2.80; CI: 1.64-4.78), BMI, allergy, and depression did not have a statistically significant association with these visit types. These associations were independent of insurance coverage, which was not statistically associated with high-acuity visits. CONCLUSION: SDOH and CMCs were associated with high-acuity healthcare presentation in adults with sinusitis. While this study highlights how SDOH affect healthcare usage patterns among people with sinusitis, further investigation is needed to identify and address the causes of these patterns.

Transient perceptual enhancements resulting from selective shifts of exogenous attention in the central fovea.

Exogenous attention, a powerful adaptive tool that quickly and involuntarily orients processing resources to salient stimuli, has traditionally been studied in the lower-resolution parafoveal and peripheral visual field.1-4 It is not known whether and how it operates across the 1° central fovea where visual resolution peaks.5,6 Here we investigated the dynamics of exogenous attention in the foveola. To circumvent the challenges posed by fixational eye movements at this scale, we used high-precision eye-tracking and gaze-contingent display control for retinal stabilization.7 High-acuity stimuli were briefly presented foveally at varying delays following an exogenous cue. Attended and unattended locations were just a few arcminutes away from the preferred locus of fixation. Our results show that for short temporal delays, observers' ability to discriminate fine detail is enhanced at the cued location. This enhancement is highly localized and does not extend to the nearby locations only 16' away. On a longer timescale, instead, we report an inverse effect: paradoxically, acuity is sharper at the unattended locations, resembling the phenomenon of inhibition of return at much larger eccentricities.8-10 Although exogenous attention represents a mechanism for low-cost monitoring of the environment in the extrafoveal space, these findings show that, in the foveola, it transiently modulates vision of detail with a high degree of resolution. Together with inhibition of return, it may aid visual exploration of complex foveal stimuli.11.

The Utility of Extended Criteria Donor Livers in High Acuity Liver Transplant Recipients.

BACKGROUND: Although the use of extended criteria donor (ECD) liver allografts has gained momentum as a potential method by which to expand the donor pool, their use largely remains relegated to low acuity liver transplant (LT) recipients. Thus, we sought to examine whether such grafts also have utility in high acuity (Model for End-Stage Liver Disease [MELD] ≥ 35) recipients. STUDY DESIGN: Extended criteria donors were defined as donor age > 60 years, hepatitis C virus positive donor, split livers, livers with cold ischemia time > 12 h, donor after cardiac death livers, or having macrosteatosis > 30%. Outcomes were compared between standard liver (SL) and ECD grafts in recipients with MELD ≥ 35. RESULTS: Of 225 patients, 46 (20.4%) received an ECD liver and 179 (79.6%) received a SL. Extended criteria donor graft recipients had significantly higher levels of post-LT maximal transaminases and rate of early allograft dysfunction. Nonetheless, high acuity ECD graft recipients had similar short- and long-term patient survival compared to SL recipients, with 1-,3-, and 5-year survivals of 86.9%, 82.3%, 79.3% and 86.9%, 80.5%, and 75.4%, respectively (P = .674). There were also no significant differences in graft survival or rejection-free survival between the 2 groups. CONCLUSION: The lack of inferior patient/graft survival among high acuity ECD graft recipients suggests that ECD livers present a viable method by which to expand the donor pool for this group of patients.

Point-of-care ultrasound of the heart and lungs in patients with respiratory failure: a pragmatic randomized controlled multicenter trial.

BACKGROUND: Point-of-care ultrasound is a focus oriented tool for differentiating among cardiopulmonary diseases. Its value in the hands of emergency physicians, with various ultrasound experience, remains uncertain. We tested the hypothesis that, in emergency department patients with signs of respiratory failure, a point-of-care cardiopulmonary ultrasound along with standard clinical examination, performed by emergency physicians with various ultrasound experience would increase the proportion of patients with presumptive diagnoses in agreement with final diagnoses at four hours after admission compared to standard clinical examination alone. METHODS: In this prospective multicenter superiority trial in Danish emergency departments we randomly assigned patients presenting with acute signs of respiratory failure to intervention or control in a 1:1 ratio by block randomization. Patients received point-of-care cardiopulmonary ultrasound examination within four hours from admission. Ultrasound results were unblinded for the treating emergency physician in the intervention group. Final diagnoses and treatment were determined by blinded review of the medical record after the patients´ discharge. RESULTS: From October 9, 2015 to April 5, 2017, we randomized 218 patients and included 211 in the final analyses. At four hours we found; no change in the proportion of patients with presumptive diagnoses in agreement with final diagnoses; intervention 79·25% (95% CI 70·3-86·0), control 77·1% (95% CI 68·0-84·3), an increased proportion of appropriate treatment prescribed; intervention 79·3% (95% CI 70·3-86·0), control 65·7% (95% CI 56·0-74·3) and of patients who spent less than 1 day in hospital; intervention n = 42 (39·6%, 25·8 38·4), control n = 25 (23·8%, 16·5-33·0). No adverse events were reported. CONCLUSIONS: Focused cardiopulmonary ultrasound added to standard clinical examination in patients with signs of respiratory failure had no impact on the diagnostic accuracy, but significantly increased the proportion of appropriate treatment prescribed and the proportion of patients who spent less than 1 day in hospital. TRIAL REGISTRATION: https://clinicaltrials.gov/ , number NCT02550184 .

Circuit Reorganization Shapes the Developing Human Foveal Midget Connectome toward Single-Cone Resolution.

The human visual pathway is specialized for the perception of fine spatial detail. The neural circuitry that determines visual acuity begins in the retinal fovea, where the resolution afforded by a dense array of cone photoreceptors is preserved in the retinal output by a remarkable non-divergent circuit: cone → midget bipolar interneuron → midget ganglion cell (the "private line"). How the private line develops is unknown; it could involve early specification of extremely precise synaptic connections or, by contrast, emerge slowly in concordance with the gradual maturation of foveal architecture and visual sensitivity. To distinguish between these hypotheses, we reconstructed the midget circuitry in the fetal human fovea by serial electron microscopy. We discovered that the midget private line is sculpted by synaptic remodeling beginning early in fetal life, with midget bipolar cells contacting a single cone by mid-gestation and bipolar cell-ganglion cell connectivity undergoing a more protracted period of refinement.

Nurses' knowledge regarding pain management in high acuity care units: A case study of Palestine.

BACKGROUND: Most patients who have been hospitalized at some point in time must have experienced a measure of pain despite improvements in health-care systems. Globally, there is a dearth in information with regard to pain management. Pain management is an essential process for nurses because they spend most time of the day with the patients. Therefore, nurses' level of knowledge and positive attitudes toward pain management reflect this vital and significant role played by nurses in critical care units. AIMS: The aims of this are to evaluate the level of knowledge and attitude of nurses regarding pain management in high acuity care units of Palestine. METHODS: For this cross-sectional descriptive study, data were obtained from seven hospitals in Palestine. Nurses were recruited from high acuity care units, including nurses from the medical and surgical wards. Their knowledge on the degree of pain was measured using the survey for "Knowledge and Attitudes Survey Regarding Pain." RESULTS: About 123 nurses took part in the survey. The total mean score of correct answers for the 39 questions asked was 17.4 ± 4.2, which is considered to be less than the pass mark of 19.5. There were no statistically significant differences between the nurses' total average score and demographic characteristics, except for their initial level of education. CONCLUSIONS: The results of this study showed that Palestinian nurses in critical care units possess inadequate knowledge about pain management. Furthermore, there are inconsistencies in their attitudes and practices which require further research. There is a need for the council of health professionals to lay emphasis on pain management through continuous training and enlightenment of nurses to equip them with more knowledge and positive attitudes toward pain management.

Diamond Devices for High Acuity Prosthetic Vision.

Retinal implants restore a sense of vision, for a growing number of users worldwide. Nevertheless, visual acuities provided by the current generation of devices are low. The quantity of information transferable to the retina using existing implant technologies is limited, far below receptor cells' capabilities. Many agree that increasing the information density deliverable by a retinal prosthesis requires devices with stimulation electrodes that are both dense and numerous. This work describes a new generation of retinal prostheses capable of upscaling the information density conveyable to the retina. Centered on engineered diamond materials, the implant is very well tolerated and long-term stable in the eye's unique physiological environment and capable of delivering highly versatile stimulation waveforms - both key attributes in providing useful vision. Delivery of high-density information, close to the retina with the flexibility to alter stimulation parameters in situ provides the best chance for success in providing high acuity prosthetic vision.

Fgf8 Expression and Degradation of Retinoic Acid Are Required for Patterning a High-Acuity Area in the Retina.

Species that are highly reliant on their visual system have a specialized retinal area subserving high-acuity vision, e.g., the fovea in humans. Although of critical importance for our daily activities, little is known about the mechanisms driving the development of retinal high-acuity areas (HAAs). Using the chick as a model, we found a precise and dynamic expression pattern of fibroblast growth factor 8 (Fgf8) in the HAA anlage, which was regulated by enzymes that degrade retinoic acid (RA). Transient manipulation of RA signaling, or reduction of Fgf8 expression, disrupted several features of HAA patterning, including photoreceptor distribution, ganglion cell density, and organization of interneurons. Notably, patterned expression of RA signaling components was also found in humans, suggesting that RA also plays a role in setting up the human fovea.

Evaluating the effect of emergency department crowding on triage destination.

BACKGROUND: Emergency Department (ED) crowding has been studied for the last 20 years, yet many questions remain about its impact on patient care. In this study, we aimed to determine if ED crowding influenced patient triage destination and intensity of investigation, as well as rates of unscheduled returns to the ED. We focused on patients presenting with chest pain or shortness of breath, triaged as high acuity, and who were subsequently discharged home. METHODS: This pilot study was a health records review of 500 patients presenting to two urban tertiary care EDs with chest pain or shortness of breath, triaged as high acuity and subsequently discharged home. Data extracted included triage time, date, treatment area, time to physician initial assessment, investigations ordered, disposition, and return ED visits within 14 days. We defined ED crowding as ED occupancy greater than 1.5. Data were analyzed using descriptive statistics and the χ(2) and Fisher exact tests. RESULTS: Over half of the patients, 260/500 (52.0%) presented during conditions of ED crowding. More patients were triaged to the non-monitored area of the ED during ED crowding (65/260 (25.0%) vs. 39/240 (16.3%) when not crowded, P = 0.02). During ED crowding, mean time to physician initial assessment was 132.0 minutes in the non-monitored area vs. 99.1 minutes in the monitored area, P <0.0001. When the ED was not crowded, mean time to physician initial assessment was 122.3 minutes in the non-monitored area vs. 67 minutes in the monitored area, P = 0.0003. Patients did not return to the ED more often when triaged during ED crowding: 24/260 (9.3%) vs. 29/240 (12.1%) when ED was not crowded (P = 0.31). Overall, when triaged to the non-monitored area of the ED, 44/396 (11.1%) patients returned, whereas in the monitored area 9/104 (8.7%) patients returned, P = 0.46. CONCLUSIONS: ED crowding conditions appeared to influence triage destination in our ED leading to longer wait times for high acuity patients. This did not appear to lead to higher rates of return ED visits amongst discharged patients in this cohort. Further research is needed to determine whether these delays lead to adverse patient outcomes.

Preparation for high-acuity clinical placement: confidence levels of final-year nursing students.

AIM: To measure final-year nursing students' preparation for high-acuity placement with emphasis on clinical skill performance confidence. BACKGROUND: Self-confidence has been reported as being a key component for effective clinical performance, and confident students are more likely to be more effective nurses. Clinical skill performance is reported to be the most influential source of self-confidence. Student preparation and skill acquisition are therefore important aspects in ensuring students have successful clinical placements, especially in areas of high acuity. Curriculum development should aim to assist students with their theoretical and clinical preparedness for the clinical environment. METHOD: A modified pretest/posttest survey design was used to measure the confidence of third-year undergraduate nursing students (n = 318) for placement into a high-acuity clinical setting. The survey comprised four questions related to clinical placement and prospect of participating in a cardiac arrest scenario, and confidence rating levels of skills related to practice in a high-acuity setting. Content and face validity were established by an expert panel (α = 0.90) and reliability was established by the pilot study in 2009. Comparisons were made between confidence levels at the beginning and end of semester. RESULTS: Student confidence to perform individual clinical skills increased over the semester; however their feelings of preparedness for high-acuity clinical placement decreased over the same time period. Reported confidence levels improved with further exposure to clinical placement. CONCLUSION: There may be many external factors that influence students' perceptions of confidence and preparedness for practice. Further research is recommended to identify causes of poor self-confidence in final-year nursing students.